Marine Mammal Protection Act; Stock Assessment Report for the Northern Sea Otter in Washington, 16688-16691 [2019-08056]

Agencies

• Fish and Wildlife Service
• DEPARTMENT OF THE INTERIOR

[Federal Register Volume 84, Number 77 (Monday, April 22, 2019)]
[Notices]
[Pages 16688-16691]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2019-08056]


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DEPARTMENT OF THE INTERIOR

Fish and Wildlife Service

[FWS-R1-ES-2018-N091; FF01EWFW00-FXES111601M000]


Marine Mammal Protection Act; Stock Assessment Report for the 
Northern Sea Otter in Washington

AGENCY: Fish and Wildlife Service, Interior.

ACTION: Notice of availability; response to comments.

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SUMMARY: In accordance with the Marine Mammal Protection Act of 1972, 
as amended, we, the U.S. Fish and Wildlife Service, have revised our 
stock assessment report for the northern sea otter stock in the State 
of Washington. We now make the final revised stock assessment report 
available to the public.

ADDRESSES: Document Availability: You may obtain a copy of the stock 
assessment report from our website at https://www.fws.gov/wafwo. 
Alternatively, you may contact the Washington Fish and Wildlife Office, 
510 Desmond Dr., Suite 102, Lacey, WA 98503; telephone: (360) 753-9440.

FOR FURTHER INFORMATION CONTACT: Deanna Lynch, at the above street 
address, by telephone (360) 753-9545), or by email 
([email protected]). Persons who use a telecommunications device for 
the deaf (TDD) may call the Federal Relay Service at (800) 877-8339.

SUPPLEMENTARY INFORMATION: We announce the availability of the final 
revised stock assessment report (SAR) for the northern sea otter 
(Enhydra lutris kenyoni) stock in the State of Washington.

Background

    Under the Marine Mammal Protection Act of 1972, as amended (MMPA; 
16 U.S.C. 1361 et seq.), and its implementing regulations in the Code 
of Federal Regulations (CFR) at 50 CFR part 18, the U.S. Fish and 
Wildlife Service (Service) regulates the taking; import; and, under 
certain conditions, possession; transportation; purchasing; selling; 
and offering for sale, purchase, or export, of marine mammals. One of 
the goals of the MMPA is to ensure that stocks of marine mammals 
occurring in waters under U.S. jurisdiction do not experience a level 
of human-caused mortality and serious injury that is likely to cause 
the stock to be reduced below its optimum sustainable population (OSP) 
level. OSP is defined under the MMPA as ``the number of animals which 
will result in the maximum productivity of the population or the 
species, keeping in mind the carrying capacity of the habitat and the 
health of the ecosystem of which they form a constituent element'' (16 
U.S.C. 1362(9)).
    To help accomplish the goal of maintaining marine mammal stocks at 
their OSPs, section 117 of the MMPA requires the Service and the 
National Marine Fisheries Service (NMFS) to prepare a SAR for each 
marine mammal stock that occurs in waters under U.S. jurisdiction. A 
SAR must be based on the best scientific information available; 
therefore, we prepare it in consultation with established regional 
scientific review groups established under 117(d) of the MMPA. Each SAR 
must include:
    1. A description of the stock and its geographic range;
    2. A minimum population estimate, current and maximum net 
productivity rate, and current population trend;
    3. An estimate of the annual human-caused mortality and serious 
injury by source and, for a strategic stock, other factors that may be 
causing a decline or impeding recovery of the stock;
    4. A description of commercial fishery interactions;
    5. A categorization of the status of the stock; and
    6. An estimate of the potential biological removal (PBR) level.
    The MMPA defines the PBR as ``the maximum number of animals, not 
including natural mortalities, that may be removed from a marine mammal 
stock while allowing that stock to reach or maintain its [OSP]'' (16 
U.S.C. 1362(20)). The PBR is the product of the minimum population 
estimate of the stock (Nmin); one-half the maximum 
theoretical or estimated net productivity rate of the stock at a small 
population size (Rmax); and a recovery factor 
(Fr) of between 0.1 and 1.0, which is intended to compensate 
for uncertainty and unknown estimation errors. This can be written as:

PBR = (Nmin)(\1/2\ of the Rmax)(Fr)

    Section 117 of the MMPA also requires the Service and NMFS to 
review the SARs (a) at least annually for stocks that are specified as 
strategic stocks, (b) at least annually for stocks for which 
significant new information is available, and (c) at least once every 3 
years for all other stocks. If our review of the status of a stock 
indicates that it has changed or may be more accurately determined, 
then the SAR must be revised accordingly.
    A strategic stock is defined in the MMPA as a marine mammal stock 
``(A) for which the level of direct human-caused mortality exceeds the 
[PBR]

[[Page 16689]]

level; (B) which, based on the best available scientific information, 
is declining and is likely to be listed as a threatened species under 
the Endangered Species Act of 1973, [as amended] (16 U.S.C. 1531 et 
seq.) [ESA], within the foreseeable future; or (C) which is listed as a 
threatened species or endangered species under the [ESA], or is 
designated as depleted under [the MMPA]'' 16 U.S.C. 1362(19).

Stock Assessment Report History for the Northern Sea Otter in 
Washington

    The Washington sea otter SAR was last revised in August 2008. The 
Washington sea otter is not a strategic stock, thus the Service is 
required to review the stock assessment at least once every 3 years. 
The Service reviewed the Washington sea otter SAR in 2011 and concluded 
that a revision was not warranted because the status of the stock had 
not changed, nor could it be more accurately determined. However, upon 
review in 2016, the Service determined that revision was warranted 
because of changes in population estimates and distribution.
    Before releasing our draft SAR for public review and comment, we 
submitted it for technical review internally and for scientific review 
by the Pacific Regional Scientific Review Group, which was established 
under the MMPA (16 U.S.C. 1386(d)). In a January 17, 2018 (83 FR 2461), 
Federal Register notice, we made our draft SAR available for the MMPA-
required 90-day public review and comment period. Following the close 
of the comment period, we revised the SAR based on public comments we 
received (see Response to Public Comments) and prepared the final 
revised SAR.

Summary of Final Revised Stock Assessment Report for the Northern Sea 
Otter in the State of Washington

    The following table summarizes some of the information contained in 
the final revised SAR for northern sea otters in Washington State, 
which includes the stock's Nmin, Rmax, 
Fr, PBR, annual estimated human-caused mortality and serious 
injury, and status.

                                  Summary--Final Stock Assessment Report for the Northern Sea Otter in Washington State
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                                                                                                       Annual estimated
                                                                                                         human-caused
               Stock                     Nmin            Rmax             Fr              PBR       mortality and serious           Stock status
                                                                                                            injury
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Northern Sea Otter (Washington               1,806            0.20             0.1              18  Figures by specific    Non-Strategic.
 State).                                                                                             source, where known,
                                                                                                     are provided in the
                                                                                                     SAR.
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Response to Public Comments

    We received comments on the draft revised SAR from the Marine 
Mammal Commission (Commission) and the Makah Tribe. We present 
substantive issues raised in those comments that are pertinent to the 
SAR, edited for brevity, along with our responses below.
    Comment 1: The Service should conduct annual reviews of this SAR, 
given the rapid population increase. In addition, the annual reviews 
and OSP analysis should be reviewed by, and input incorporated from, 
the Pacific Scientific Review Group (PSRG) before the revised SAR is 
made available for public review and comment, as required by section 
117 of the MMPA.
    Response: As required in section 117(c) of the MMPA, the Service 
strives to meet its statutory requirement of reviewing the SAR for this 
non-strategic stock every 3 years. If our review indicates the status 
of the stock has changed or can be more accurately determined, the 
Service revises the SAR in accordance with section 117(b), which 
includes providing an opportunity for public review and consideration 
of advice offered by the PSRG. However, prior to public notification of 
the availability of a draft revised SAR, the Service seeks input from 
the PSRG to ensure it accurately reflects the best scientific 
information available at the time of preparation. In addition, the 
Service updates the PSRG on any new information and ongoing studies 
during the PSRG's annual meetings.
    The Service considers the ongoing population increase of 9 percent 
per year to be the population trajectory for almost three decades and, 
as such, does not represent significant new information that would 
warrant a review or revision on an annual basis. We appreciate the 
commenter's concern over the time it takes for review and, if 
warranted, subsequent revision of the SAR but balance that concern with 
the need to ensure our SAR accurately reflects the best available 
science and is subject to the public comment process.
    Comment 2: The Service should develop methods for estimating total 
abundance of sea otters and associated uncertainty to inform an Optimum 
Sustainable Population (OSP) analysis so that more accurate comparisons 
with carrying capacity estimates can be made.
    Response: Although the Service has provided funds to the Washington 
Department of Fish and Wildlife (WDFW) for conducting the annual summer 
census (which at least provides a minimum population estimate for 
estimating the PBR), the Service does not currently have the resources 
to develop and implement a survey method that would accurately estimate 
the total abundance and associated uncertainty for the Washington sea 
otter stock. Such a survey would most likely be cost-prohibitive 
because it would require considerably more flight and staff time in 
order to cover the full extent of the range where otters may occur. 
Although a statistically rigorous analysis to develop an estimate of 
uncertainty could potentially be developed, it would also require a 
significant investment of resources because development of a detection 
function requires observer verification. A detection function based on 
past survey data would likely not be appropriate for the following 
reasons: (a) The number of ground stations throughout the range in 
different habitat types is not sufficient; (b) the ground observers 
miss otters that are observed by the aerial observer, and aerial photo 
counts often are higher than ground observer counts, further 
complicating the ability to calculate the error; and (c) since 1989, 
there has been one consistent aerial observer, thus any confidence 
interval developed for past data may not be applicable to surveys post-
2019 when the current observer will be retiring.
    At this time, the Service does not have a reliable estimate of 
carrying capacity, and therefore, the Service has not identified the 
OSP for the Washington stock of northern sea otters. The Service is 
aware of a Ph.D. student out of the University of Washington who is 
currently working on an updated estimate of carrying capacity for

[[Page 16690]]

northern otters in Washington, which may assist the Service in 
determining a more appropriate lower end of the OSP range (i.e., 
approximately 60 percent of carrying capacity). This will allow the 
Service to provide a more accurate determination of the stock's status 
relative to OSP; however, because the population continues to increase 
at 9 percent per year, we consider it unlikely that the stock is at 
OSP. Also, see response to Comment 5.
    Comment 3: The Service should revise the discussion of fisheries 
information to indicate more precisely the nature of the Makah fishery, 
including the target species, where it is active, and whether it is a 
commercial fishery.
    Response: NMFS (under the Secretary of Commerce) has the 
responsibility under MMPA section 118 for development of the List of 
Fisheries. NMFS's regulations at 50 CFR 229.1(d) state that those 
regulations do not apply ``to Northwest treaty Indian tribal members 
exercising treaty fishing rights.'' Therefore, NMFS does not include 
the commercial fisheries operated by Northwest treaty Indian Tribes in 
the List of Fisheries. For example, in the 2016 List of Fisheries (81 
FR 20550, April 8, 2016), Treaty Indian fishing is specifically 
excluded from the Washington Puget Sound region and Washington Grays 
Harbor salmon drift gillnet fisheries, which are commercial fisheries 
in which Tribes participate. The Makah Tribe's marine set-gillnet 
fishery is a commercial treaty fishery and is included in the 
Washington northern sea otter SAR in that category accordingly. The 
fishing areas where the fishery is active are also included in this 
SAR, specifically Catch Areas 4/4A/4B/5/6A/6C. The Service does not 
have access to the number of vessels participating in this fishery. 
Landing information for fisheries in these Catch Areas has been 
provided to the Service for ESA consultations with NMFS, but it does 
not break down the information by Tribe or fishery (i.e., includes both 
drift and set gill nets), nor does it include number of vessels.
    We have reached out to NMFS to obtain reports of incidental taking 
of sea otters and have received no reports. Per NMFS' regulations, as 
mentioned above, fisheries operated by Northwest treaty Indian Tribal 
members exercising treaty fishing rights are exempt and are thus not 
subject to the reporting requirements of MMPA section 118(e). Unless a 
Tribe has their own regulations that require reporting and those 
reports are provided to NMFS and the Service, we are not privy to any 
incidental take. The Makah Tribe has provided incidental take 
information directly to the Service, per their regulations. Other 
Tribes may have similar self-reporting regulations regarding incidental 
catch of marine mammals, but we have not received reports from any 
other Tribe.
    Comment 4: The Service should consult with NMFS, Tribal 
authorities, and other relevant groups to arrange for the placement of 
observers aboard trap and gillnet fishing vessels that may pose a 
significant risk of incidentally taking sea otters within their range 
in Washington State.
    Response: Under the MMPA, only Category I and II fisheries are 
required to accommodate an observer on board their vessel(s). Category 
III fisheries are generally not required to accommodate observers 
aboard vessels due to the remote likelihood of mortality and serious 
injury of marine mammals. Any request to place an observer on board a 
vessel must originate from NMFS. The Service does not have the 
authority to request observers be placed aboard fishing vessels. The 
fisheries that may result in mortality or serious injury of sea otters 
are either Tribal or Category III fisheries, except for the Washington 
coast Dungeness crab pot fishery, which is a Category II fishery. In 
addition, the pots are set and left and most of these vessels are small 
and cannot accommodate an observer on board. While an observer program 
may increase our opportunity to detect bycatch, analyses indicate that 
high levels of observer effort would be required to avoid false-
negative conclusions, even if the rate of bycatch mortality is 
substantial enough to reduce the population growth rate (Hatfield et 
al. 2011). The Service will continue to work with the WDFW, NMFS, and 
Tribes to explore options for assessing sea otter bycatch, subject to 
funding availability.
    Comment 5: The commenter asserted the recovery factor should be 
0.75 or higher for the following reasons: (a) The SAR does not follow 
NMFS guidelines, (b) a State listing status cannot be used in the 
rationale for a recovery factor, (c) the WDFW proposed to change the 
State's status from endangered to threatened in February 2018, and (d) 
the current (2017) estimate indicates the population is approaching 
carrying capacity and has attained OSP.
    Response: The Service appreciates and supports the efforts of NMFS 
in developing their Office of Protected Species Technical Memorandum 
and the 2016 Guidelines for Preparing Stock Assessment Reports. 
However, these NMFS guidelines have not been adopted by the Service, 
and, while we consider the information contained within them to the 
extent applicable, they are not binding on the Service.
    The WDFW's proposed change in status (Sato 2018) was not available 
at the time the SAR was developed nor before the SAR was made available 
for public comment, thus could not be considered in this SAR. 
Regardless, the recovery factor of 0.1 was not entirely based on the 
State listing status. As was recommended to the Service by the PSRG, we 
relied on the Taylor et al. (2003) factor for a small population 
(consisting of between 1,500 and 7,500 individuals) that has an 
increasing trend, but is considered vulnerable, regardless of listing 
status. The Washington sea otter stock is within the range considered 
to be a small population (whether or not a newer population estimate is 
used) and is considered to be vulnerable because of their restricted 
range making more than 50 percent of the stock vulnerable to a 
potential catastrophe, such as an oil spill, at any point in time. 
Therefore, the Service continues to agree with the recommendation made 
by the PSRG to use a recovery factor of 0.1.
    A carrying capacity estimate was produced by Laidre et al. (2011); 
however, the Service does not consider this to be a viable estimate for 
the full range of this stock for the following reasons:
    (1) This carrying capacity estimate relied on population density 
estimates associated with rocky habitat in Washington where the 
population has continued to grow at about 5 percent per year.
    (2) Laidre et al. (2011) relied upon density estimates developed 
for southern sea otters for the mixed and sandy habitat in Washington. 
This is not an appropriate density estimate to apply because southern 
sea otters are food limited, whereas Washington sea otters are not. An 
appropriate carrying capacity estimate for Washington sea otters needs 
to be based on food availability within the different habitat types 
that occur in Washington.
    (3) Some areas that Laidre et al. (2011) delineated as rocky 
habitat should have been delineated as mixed or sandy, within which a 
more appropriate density estimate should be applied.
    (4) Subsequent to the data relied upon by Laidre et al. (2011), 
exponential population growth has occurred within the areas that are 
primarily mixed and sandy habitat types. This type of population growth 
is not an indicator that a population is approaching carrying capacity.
    (5) Because there is evidence that Washington sea otters move 
around within their range more than otters in

[[Page 16691]]

other stocks, basing a density estimate on a population estimate taken 
only once per year may not provide a realistic evaluation of the use of 
the habitat. Although Laidre et al. (2011) provided a total carrying 
capacity estimate of 1,854 sea otters for this stock, this is not a 
good representation of the number of otters the habitat in Washington 
is capable of supporting. In addition, the rate at which the Washington 
sea otter population is increasing (i.e., average rate of 9 percent per 
year 1989 to 2016) indicates the stock has not reached it's carrying 
capacity. Without an updated estimate of carrying capacity, the status 
of the Washington sea otter stock relative to OSP cannot be determined 
at this time; however, because the population is increasing at such a 
significant rate, it is unlikely to be at OSP.
    Thus, the Service has retained the recovery factor of 0.1 in the 
revised SAR. As new information becomes available, the Service may 
reevaluate our recovery factor in future revisions.
    Comment 6: Table 1 should reflect the most recent data available. 
In addition, the specific references to the Makah Tribe should be 
removed and all Tribal information be referred to as ``treaty tribal 
fisheries.''
    Response: The SAR covers the time period of 2011-2015/2016, which 
includes data available at the time the SAR was revised. As indicated 
in response to Comment 1, the process for review and revision of a SAR 
can take a considerable amount of time even before making it available 
for public comment. If the Service were to update the SAR to include 
data outside the time period provided in the draft revised SAR, the 
changes would be significant enough to require republication of a new 
draft revised SAR and, thus, the process would begin again. This could 
perpetually delay finalization of the SAR. Instead, the next revision 
of the SAR will include the more recent data.
    Per section 117(a)(4) of the MMPA, the Service is required to 
describe the commercial fisheries that interact with the stock. The 
Northern Washington Marine Set Gillnet Fishery is a commercial fishery 
that reported sea otter takes during the time period included in the 
SAR and, therefore, must be included in Table 1. We have changed 
reference to the fishery being a ``Makah fishery'' to a ``Tribal 
fishery'' and have removed line 1 referencing Areas 4/4A from the table 
as there was no active fishery in these areas during the time period of 
this SAR.
    Comment 7: Speculation about the possibility that sea otters could 
be trapped in crab fishing pots should be removed from the SAR. There 
is no direct evidence of mortality in Washington, and any mortalities 
would have been documented in social media. Circumstantial evidence 
indicates that, if any mortality is occurring, it is very minor and is 
not impacting the population.
    Response: As discussed in the SAR, the data we relied upon was not 
based on experimental efforts. There is direct evidence of sea otters 
in California and Alaska being trapped and drowned in crab pot gear 
that is identical to gear used within the range of the sea otter in 
Washington, and we cannot be sure that all otters that become trapped 
and subsequently die will be reported via social media. The assumption 
that the population would not be growing at its current rate if it was 
experiencing mortality in the crab fishery is not necessarily accurate. 
While it appears that the population is growing at 20 percent in the 
southern portion of the range, the population as a whole is growing at 
9 percent. A significant number of pups continues to be documented in 
the northern portion of the range, and it is more likely that the 
growth in the south is being supplemented by births in the northern 
portion. Finally, both the PSRG and Commission have recommended that we 
include the information regarding the unknowns in the SAR.
    Comment 8: The section on ``Harvest by Northwest treaty Indian 
Tribes'' does not belong in the SAR and should be removed as it does 
not follow NMFS guidelines.
    Response: As stated in our response to Comment 5, the NMFS 
guidelines have not been adopted and are not binding on the Service. 
Section 117 of the MMPA provides the essential elements that should be 
addressed in a SAR; however, the Service is not precluded from 
including other items as it sees fit. As this stock is subject to 
potential harvest by Tribes that the Service does not consider exempt 
under MMPA, the Service believes it is necessary to include this 
statement in our document.
    Comment 9: The mortality rate information in the SAR does not 
reflect the best available science and is inconsistent with the SAR 
guidelines developed by NMFS. In particular, the SAR does not provide a 
conclusion on whether the total fishery mortality and serious injury 
rate is approaching a zero mortality and serious injury rate.
    Response: Section 117(a)(3) requires that the Service provide an 
estimate of all human-caused mortality and serious injury. While our 
data are limited due to lack of observer coverage and uncertainties, we 
have based our estimate on the best data available, including beach-
cast carcasses that represent other sources of human-caused mortality. 
We clearly indicate that the minimum level of all human caused 
mortality and serious injury is at least one sea otter per year and may 
be higher. Although the known human-caused mortality and serious injury 
is less than PBR, we are unable to definitively state that the total 
mortality and serious injury of sea otters due to human-caused 
mortalities and serious injuries is insignificant and approaching a 
zero mortality and serious injury rate because of the lack of observer 
data for commercial fisheries that may interact with sea otters.

Authority

    The authority for this action is the Marine Mammal Protection Act 
of 1972, as amended (16 U.S.C. 1361 et seq.)

    Dated: April 3, 2019.
Margaret E. Everson,
Principal Deputy Director, U.S. Fish and Wildlife Service Exercising 
the Authority of the Director for the U.S. Fish and Wildlife Service.
[FR Doc. 2019-08056 Filed 4-19-19; 8:45 am]
 BILLING CODE 4333-15-P